Multimode broad area semiconductor laser diodes (BALs) typically emit beams having a higher slow-axis beam-parameter-product (BPP) and a lower slow axis brightness (power/BPP2) than beams emitted by similar single-mode semiconductor laser diodes. The poorer slow axis beam quality of the beams emitted by the BALs can be a result of a larger slow axis divergence and an associated lateral shape of the multiple optical modes in the emitted beams. Reducing the width of the emitters of the BALs can improve brightness, but output power typically suffers. Therefore, devices and methods are needed to provide BALs with improved slow-axis performance at higher powers.